<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
  <script src="jquery.js"></script>
  <style>
  .m-gridup{
    position: relative;
  }

  .m-gridup-item{
    position: absolute;
    transition: all .6s ease;
    z-index: 5;
  }

  .m-gridup-bg{
    border: 3px dashed #ccc;
    box-sizing: border-box;
    z-index: 1;
    position: absolute;
    left: 0;
    top: 0;
  }

  .wrapper>.item>.handle{
    height: 50px;
    background: rgba(255,255,255,.3)
  }

  .bar{
    height: 200px;
    width: 640px;
    margin-bottom: 20px;
  }
  .head {
    position: absolute;
    top: 0;
    height: 200px;
    left: 0;
    right: 0;
  }
  .wrap{
    padding: 50px;
    position: absolute;
    top: 200px;
    left: 0;
    right: 0;
    bottom: 0;
    overflow: auto;
  }
  </style>
</head>
<body>
  <div class="head">
    <button onclick="console.log($('.wrapper').offset(), $('.wrapper').position())">测试父元素</button>
  </div>
  <div class="wrap">
    <div class="bar item"></div>
    <div class="wrapper">
      <div class="item">
        <div class="handle">1</div>
      </div>
      <div class="item">
        <div class="handle">2</div>
      </div>
      <div class="item">
        <div class="handle">3</div>
      </div>
      <div class="item">
        <div class="handle">4</div>
      </div>
      <div class="item">
        <div class="handle">5</div>
      </div>
      <div class="item">
        <div class="handle">6</div>
      </div>
    </div>
  </div>
  <script src="basic.js"></script>
</body>
</html>